Sonic
the Hedgehog.

Green Hill starts here. The original Genesis game, running in your browser.

SEGA GENESIS / MEGA DRIVE

Ready to run.

Keyboard, touch, or a USB / Bluetooth controller.

512 KB cartridge · Local browser emulation

Start the game to load the verified Genesis cartridge.

OPTIONAL CHEATS

Your rules.

Choose each assist independently. All three start off.

InvincibilityEnemies and damage hazards cannot hurt Sonic or knock him back. Rings stay collectible. Pits, drowning, crushing and the time limit still use the original game rules.Keep rings when hitSonic still takes the hit and gets knocked back, but no rings scatter or disappear. A hit with zero rings can still kill him.Unlimited livesDying and restarting a stage do not subtract a life.

Original game rules. All assists are off.

YOUR CONTROLS

Pick up speed.

Move / look: Arrow keys
Jump / spin attack: X, S or Z
Roll while moving: ↓
Start / game pause: Enter

Press Enter / Start on the title screen. Jump onto enemies to attack. Press Down while running to roll. Sonic 1 has no spin dash.

A standard gamepad maps bottom face → A, right face → B, left face → C; Start / Menu → Start. All three Genesis face buttons jump. Connect and press a button, then assign it to Player 1 below the game.

KEEP YOUR POSITION

Game snapshots.

Save your exact position in the original game.

No browser snapshot yet.

These are emulator snapshots for this verified ROM and core. Keep a downloaded copy; browser data can be cleared. The original Sonic 1 cartridge has no battery save. Your current cheat selections remain active when loading a snapshot.

Preservation and runtime

The supplied SMD archive and its original bytes are retained. The browser cartridge reversibly removes the SMD copier header and interleaving; its program and asset bytes are unchanged. This edition uses self-hosted EmulatorJS 4.2.3 and a pinned Genesis Plus GX core.

File checksums and intake · Cheat behavior and verification · Runtime source notes · EmulatorJS license · Genesis Plus GX license

Optional cheats alter instructions in emulator memory and restore them when switched off. The cartridge file stays unchanged. Snapshots check game identity, format and checksum, then require a complete native serializer match after loading.

Sonicthe Hedgehog.

Ready to run.

Your rules.

Sonic
the Hedgehog.